1. Field of the Invention
This invention relates to vessel propulsion systems, and in particular to a hydraulic thruster for vessel.
2. Background of the Invention
Marine thrusters typically mount on barges and flat boats, and are used as propulsion for these vessels. One type of marine thruster employs a prime mover such as a diesel engine driving a hydraulic pump, together known as a “power pack”, and the resultant pressurized hydraulic fluid may be employed to drive a propeller attached to a lower unit.
One problem with existing marine thruster system designs is the absence of a quick and easy means to add additional thrusters to the system, as required. It would be desirable to provide a hydraulic thruster for vessel which may be readily attached as required to an existing marine hydraulic thruster system for a flat vessel, as required by changed weight loading and/or thruster requirements.
In addition, there are a number of problems with existing marine hydraulic thrusters themselves. One problem is that existing hydraulic marine thrusters can only extend and retract their propellers units around twenty inches. It would be desirable to be able to extend and retract the propeller unit a greater range, in the order of at least four feet, to accommodate deeper vessels and varied thrusting requirements.
Another problem with existing marine hydraulic thrusters is the challenge involved in shipping them. It would be desirable to provide a marine hydraulic thruster which can fold into a compact size for shipping, including containerized shipping, without having to disassemble the thruster to reduce its shipping cube.
Still another problem associated with currently-available marine thrusters is the absence of a secure down-stop when the thruster is tilted completely down. Accordingly, it would be advantageous to provide positive, redundant down-stops to securely prevent further tilting of a fully down-tilted thruster when it is developing full forward thrust.
Yet another problem associated with existing marine hydraulic thrusters is the absence of a means of securely fastening a thruster to the deck of a vessel upon which it is to be mounted, short of physically welding the thruster base directly to the vessel deck.
Therefore, it would be desirable to provide a hydraulic thruster for vessel which may be readily attached as required to an existing marine hydraulic thruster system for a flat vessel, which is extendible over a significantly greater range than existing thrusters, which can fold into a compact size for shipping, whose design incorporates a positive, redundant down-stop, and means of securely and removably mounting the thruster to a vessel.